Can you explain to me how a certified check works for payment for a car?

The benefit of a certified check is for the seller, not necessarily you (although you are right about it being safer than taking cash). It comes directly from the bank, so the buyer knows that the funds are good and the check won't bounce. Usually, you work out the amount of the purchase with the seller and then go to the bank. The bank then writes out the check for you; you just tell them who to make it out to and for what amount. The cost of the check will depend on the bank. Some banks offer 1 per day free, and others will charge a small fee, usually around $5 or so. You'll need to ask the bank about returning a check that you don't use. I've never not used a check I had them make out, so I'm not sure about the policy on that.

If banking doesn't satisfy you, you can make a money order at the post office. put the name of the person yor paying, how much and voila! If your selling your car, a certified check from the buyer just means you won't get a bad personnal check. It means the bank said,,yup! the money is there! that's it

Nowdays, with so many scammers, frankly, I would prefer cash rather than a certified check if I was a seller. I pretty much always bought cars with cash from private parties too. Of course, I mostly dealt in cheaper stuff. Under $3000. A few times I would take checks and immediately go cash them. Believe it or not, cashiers checks CAN be canceled or "stop payments" issued so they are not really protecting the person getting one.